Recent advances in electron microscopy have opened up new dimensions and perspectives in the field of morphology, and these are presently being integrated with biochemical and physiopathological phenomena occurring in cells, tissues, and organs. Methods such as freeze-fracture, freeze-etching, scanning, and high-voltage electron microscopy have contributed immensely to this progress, as well as to the study of smooth muscle tissue and contractile cells in general. The articles composing this book have been selected and edited with the purpose of updating and reviewing the most important aspects of smooth muscle cells as revealed by the integration of these submicroscopic techniques. The chapters of this volume have been prepared by some of the most authoritative experts in the discipline. Therefore each article not only offers the reader a concise review of the specific topic, but also seeks to highlight areas that require further investigation. Much of the volume is presented in an illustrative format so as to emphasize the remarkable results obtainable by the combination of the aforementioned methods, which allow a better appreciation of smooth muscle structure and ultrastructure. This volume, like others in the series, is intended not only for researchers in the field, but also for graduate students of histology, embryology, anatomy, physiology, and pathology in both medical and veterinary colleges. My hope is that this book will prove to be a valuable academic resource to the audience of the world in this fascinating and expanding field.